make quantity flag work with pflag package

pkg/api/resource/quantity_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	fuzz "github.com/google/gofuzz"
+	"github.com/spf13/pflag"
 	"speter.net/go/exp/math/dec/inf"
 )
 
@@ -487,3 +488,10 @@ func TestQFlagSet(t *testing.T) {
 		t.Errorf("Unexpected result %v != %v", e, a)
 	}
 }
+
+func TestQFlagIsPFlag(t *testing.T) {
+	var pfv pflag.Value = qFlag{}
+	if e, a := "quantity", pfv.Type(); e != a {
+		t.Errorf("Unexpected result %v != %v", e, a)
+	}
+}